diff --git a/Source/externs.m b/Source/externs.m
index 57f1dc8f4..9332f93b2 100644
--- a/Source/externs.m
+++ b/Source/externs.m
@@ -32,6 +32,7 @@
 #import "AppKit/NSApplication.h"
 #import "AppKit/NSEvent.h"
 #import "AppKit/NSAppearance.h"
+#import "AppKit/NSFontCollection.h"
 
 // Global strings
 NSString *NSModalPanelRunLoopMode = @"NSModalPanelRunLoopMode";
@@ -812,6 +813,22 @@ const NSAppearanceName NSAppearanceNameAccessibilityHighContrastVibrantDark =
   @"NSAppearanceNameAccessibilityHighContrastVibrantDark";
 const NSAppearanceName NSAppearanceNameLightContent = @"NSAppearanceNameLightContent";
 
+// Values for NSFontCollectionAction
+NSFontCollectionActionTypeKey const NSFontCollectionWasShown = @"NSFontCollectionWasShown";
+NSFontCollectionActionTypeKey const NSFontCollectionWasHidden = @"NSFontCollectionWasHidden";
+NSFontCollectionActionTypeKey const NSFontCollectionWasRenamed = @"NSFontCollectionWasRenamed";
+
+// Standard named collections
+NSFontCollectionName const NSFontCollectionAllFonts = @"NSFontCollectionAllFonts";
+NSFontCollectionName const NSFontCollectionUser = @"NSFontCollectionUser";
+NSFontCollectionName const NSFontCollectionFavorites = @"NSFontCollectionFavorites";
+NSFontCollectionName const NSFontCollectionRecentlyUsed = @"NSFontCollectionRecentlyUsed";
+
+// Collections
+NSFontCollectionMatchingOptionKey const NSFontCollectionIncludeDisabledFontsOption = @"NSFontCollectionIncludeDisabledFontsOption";
+NSFontCollectionMatchingOptionKey const NSFontCollectionRemoveDuplicatesOption = @"NSFontCollectionRemoveDuplicatesOption";
+NSFontCollectionMatchingOptionKey const NSFontCollectionDisallowAutoActivationOption = @"NSFontCollectionDisallowAutoActivationOption";
+
 extern void __objc_gui_force_linking (void);
 
 void